The present invention relates to deformable closures for containers provided with bungs or orifices which have generally cylindrical walls with interior and exterior edges that can be sealed-against. More particularly, the invention relates to tamper-proof closures capable of plugging and sealing orifices in which the orifice walls have various configurations such as internal threads for engaging screw-type closures.
Previously known deformable orifice closures are described in patents such as the following: U.S. Pat. No. 3,648,874 describes a cap-like closure capable of being constricted around the threads on a bottle so female threads are formed in the cap and secure the cap to the bottle. U.S. Pat. No. 3,742,898 describes a beer barrel bung having side walls which are relaxed upon insertion but become compressed by the pressure within the vessel pushing on the bottom wall of the bung. U.S. Pat. No. 4,046,168 describes resilient plugs for closing the ends of tubes in order to prevent inadvertent entry of foreign material. U.S. Pat. No. 4,202,463 describes an orifice closure comprising a wall contacting element and a separately installed inner core for sealing engagement in a generally circular orifice. U.S. Pat. No. 4,287,996 describes a flexible closure having an annular portion connected by a hinge to a central portion so that the annular portion pivots and is compressed between the central portion and a smooth orifice wall.